Design a Ride-Hailing Service (Uber / Lyft)

Geo, Maps & MarketplacesHarddesign-ride-hailing

Design a Ride-Hailing Service (Uber / Lyft)

Design the matching core: millions of drivers streaming location updates, riders requesting nearby cars, and a dispatch decision that must be made in seconds and never double-assign.

Geospatial IndexingDispatch MatchingLocation StreamingState Machines

Traffic & Capacity Estimates:

5M active drivers · 1M concurrent trips · 600k location updates/second · match in <5s

Functional Requirements

•Ingest driver location updates every few seconds and keep a queryable spatial index.
•Find candidate drivers near a rider and dispatch the request by ETA and acceptance likelihood.
•Manage the trip lifecycle as an explicit state machine through to payment.
•Stream live driver position to the rider's map during pickup and the trip.

Non-Functional Requirements

•Nearby-driver query under 100ms at p99.
•A driver must never be assigned to two trips — matching is a critical section.
•The system must keep dispatching during a regional surge, degrading match quality rather than failing.

Back-of-the-Envelope Math

5M drivers updating every 4s = 1.25M writes/second of location data, almost all of it immediately overwritten.
Location history at 1.25M/s * 50 bytes = 62 MB/s if retained — retention policy is a real cost decision.

Key Architectural Trade-offs

Geohash/S2/H3 cell indexing (cheap, cell-boundary edge cases) vs a quadtree (precise, rebalancing cost under movement) — both beat a naive distance scan.
Live locations belong in memory, not in the durable store; the durable trip record and the ephemeral position stream have opposite requirements.
Optimistic dispatch to several drivers at once fills cars faster and creates race conditions that need a lock or a conditional write to settle.

Click or drag a component onto the canvas, then connect the handles to draw the data flow.

3 nodes · 2 edges

Components · 35

Client & Edge4

Compute & Gateway7

Storage & Caching11

Messaging & Streaming6

Coordination & Ops5

Intelligence2

React Flow